[ 081/150] drm/i915: Preserve the FDI line reversal override bit on CPT

Greg Kroah-Hartman
2013-02-27T01:00:27Z

From: Damien Lespiau <damien.lespiau@intel.com>

commit 3e68320ef84528604d971afc3cadfbe208bef001 upstream.

The FDI link has supported link reversal to make the PCB layout
engineer's life easier for quite a while and we have always presered
this bit as we programmed FDI_RX_CTL with a read/modify/write sequence.

We're trying to take a bit more control over what the BIOS leaves in
various register and with the introduction of DDI, started to program
FDI_RX_CTL fully.

There's a fused bit to indicate DMI link reversal and FDI defaults to
mirroring that configuration. We have a bit to override that behaviour
that we need to preserve from the BIOS.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/i915_reg.h | 2 +-
drivers/gpu/drm/i915/intel_crt.c | 14 +++++++++-----
drivers/gpu/drm/i915/intel_ddi.c | 6 ++----
4 files changed, 13 insertions(+), 11 deletions(-)

--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -919,7 +919,7 @@ typedef struct drm_i915_private {
bool hw_contexts_disabled;
uint32_t hw_context_size;

- bool fdi_rx_polarity_reversed;
+ u32 fdi_rx_config;

struct i915_suspend_saved_registers regfile;

--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3927,7 +3927,7 @@
#define FDI_10BPC (1<<16)
#define FDI_6BPC (2<<16)
#define FDI_12BPC (3<<16)
-#define FDI_LINK_REVERSE_OVERWRITE (1<<15)
+#define FDI_RX_LINK_REVERSAL_OVERRIDE (1<<15)
#define FDI_DMI_LINK_REVERSE_MASK (1<<14)
#define FDI_RX_PLL_ENABLE (1<<13)
#define FDI_FS_ERR_CORRECT_ENABLE (1<<11)
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -800,10 +800,14 @@ void intel_crt_init(struct drm_device *d
dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS;

/*
- * TODO: find a proper way to discover whether we need to set the
- * polarity reversal bit or not, instead of relying on the BIOS.
+ * TODO: find a proper way to discover whether we need to set the the
+ * polarity and link reversal bits or not, instead of relying on the
+ * BIOS.
*/
- if (HAS_PCH_LPT(dev))
- dev_priv->fdi_rx_polarity_reversed =
- !!(I915_READ(_FDI_RXA_CTL) & FDI_RX_POLARITY_REVERSED_LPT);
+ if (HAS_PCH_LPT(dev)) {
+ u32 fdi_config = FDI_RX_POLARITY_REVERSED_LPT |
+ FDI_RX_LINK_REVERSAL_OVERRIDE;
+
+ dev_priv->fdi_rx_config = I915_READ(_FDI_RXA_CTL) & fdi_config;
+ }
}
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -178,10 +178,8 @@ void hsw_fdi_link_train(struct drm_crtc
FDI_RX_TP1_TO_TP2_48 | FDI_RX_FDI_DELAY_90);

/* Enable the PCH Receiver FDI PLL */
- rx_ctl_val = FDI_RX_PLL_ENABLE | FDI_RX_ENHANCE_FRAME_ENABLE |
- ((intel_crtc->fdi_lanes - 1) << 19);
- if (dev_priv->fdi_rx_polarity_reversed)
- rx_ctl_val |= FDI_RX_POLARITY_REVERSED_LPT;
+ rx_ctl_val = dev_priv->fdi_rx_config | FDI_RX_ENHANCE_FRAME_ENABLE |
+ FDI_RX_PLL_ENABLE | ((intel_crtc->fdi_lanes - 1) << 19);
I915_WRITE(_FDI_RXA_CTL, rx_ctl_val);
POSTING_READ(_FDI_RXA_CTL);
udelay(220);